1. Field
The present invention relates to current flow in planar conductors, and, more particularly, to structural characteristics of such planar conductors to regulate characteristics of such current flow.
2. Description of the Related Art
An ideal power divider is a circuit network that divides power applied to an input port between any number of output ports without substantially affecting the phase relationship or otherwise causing the signals at the output ports to be substantially different from one another. There are many different types of power dividers. In practice, power dividers can introduce some level of non-similarities in amplitude and/or phase of the signal at one output port compared to a signal at another output port. This is often true of planar power dividers, where the planar width of the power divider can become large with respect to signal wavelengths. Many different types of planar power dividers have been proposed to solve this problem. While these techniques are helpful, new techniques are still sought to attenuate noncolinearity and phase noncoherence in signals at output ports of planar power dividers.
In the field of high power amplification circuits, for example, input/output matching circuitry may include a combination of distributed transmission line structures formed by relatively uniform and uninterrupted metallization impedance matching patterns (e.g., planar, multi-port power dividers) on high dielectric substrate materials and bond wires connecting the metallization patterns to the input/output terminals of an amplifier device. With increasing power levels, impedance levels generally become lower, the physical width of the active device becomes large which then necessitates a transmission line structure whose width is large and can be a significant portion of a wavelength of the power signal. This large width inherently leads to significant signal amplitude and phase non-uniformity across the connecting device/matching circuit plane. As a consequence, the outer portion of the device is generally driven more strongly than the inner section. This leads to loss of efficiency and degradation in other performance parameters, hot spots in the device periphery, and potentially reduced reliability. In effect, the large active device becomes electrically equivalent to smaller parallel devices driven non-uniformly. Industry is still searching for effective ways to reduce the amplitude and phase non-uniformities introduced by traditional transmission line structures in high power amplifiers and other devices.